RT Journal Article
T1 Dispersed alkaline substrate passive treatment technology for highly contaminated acid mine drainage: 20 years of successful application
A1 León Cortegano, Rafael
A1 Millán Becerro, Ricardo
A1 Macías Suárez, Francisco
A1 Ruiz Cánovas, Carlos
A1 Neculita, Carmen Mihaela
A1 Ayora, Carlos
A1 Nieto Liñán, José Miguel
AB Over the past two decades, Dispersed Alkaline Substrate technology (DAS) has emerged as a highly effective passive approach to treating acid mine drainage with extreme acidity and metal loading. By mixing alkaline materials - such as limestone, magnesia, barium carbonate or industrial by-products - into an inert wood-chip matrix, DAS systems maintain high porosity and neutralization capacity without rapidly clogging. This treatment technology has evolved from laboratory trials to pilot and full-scale field testing, using multi-step systems integrated with Natural Fe-Oxidizing Lagoons (NFOL) for pre-oxidation, which have demonstrated their longterm effectiveness for acidity and metal removal. The sustainability and applicability of the process has been improved by the search for new reagents (e.g. MgO for divalent metals removal, BaCO₃ for sulfate removal, wood ash or calcite-rich waste for cost reduction). Field trials in diverse regions - from the Iberian pyrite belt to South Africa, Canada, South America, Asia, Europe and Oceania - report net acid removal often exceeding 95 % and near complete retention of metal(loid)s such as Al, Cu, Zn, Pb and As. Mineralogical analyses indicate that contaminants precipitate primarily as hydroxides, oxyhydroxides, and sulfates (e.g., schwertmannite, basaluminite, barite), allowing targeted valorization of metal-rich sludges. Remaining challenges include assessing long-term reagent life under variable hydrological conditions, extending full-scale use to phosphogypsum and other industrial leachates, and developing strategies for residue stabilization and resource recovery. The aim of this review is to  synthesise these developments, assess current performance and identify future research needs for the advancement of passive DAS treatment technology.
PB Elsevier
SN 0043-1354
SN 1879-2448 (electrónico)
YR 2025
FD 2025
LK https://hdl.handle.net/10272/27395
UL https://hdl.handle.net/10272/27395
LA eng
NO León, R., Millán-Becerro, R., Macías, F., R․ Cánovas, C., Neculita, C. M., Ayora, C., & Nieto, J. M. (2026). Dispersed alkaline substrate passive treatment technology for highly contaminated acid mine drainage: 20 years of successful application. Water Research, 288, 124683. https://doi.org/10.1016/j.watres.2025.124683
NO This research was supported by ERA-MIN3 SuMRee project (PCI2024-153500), financed by MICIU/AEI/10.13039/501100011033, and by the European Union NextGeneration EU/PRTR. Ricardo Mill´an- Becerro acknowledges Juan de la Cierva Postdoctoral Fellowship (JDC2023-052111-I) supported by MCIU/AEI/10.13039/ 501100011033 and the FSE+. Funding for open access charge: Uni versidad de Huelva / CBUA.
DS Repositorio Institucional de la Universidad de Huelva
RD 1 jun 2026